PRE PROCESSOR

 

eta/DSI's extensive Preprocessing capabilities contain all of the functions necessary for expedient, high quality, finite element modeling.  Users can read in data with DSI's CAD interface, build their model from scratch, read in an existing model, or a combination of the approaches.

 

CAD INTERFACE

 

eta/DSI enables users to read in CAD geometry data from the following CAD systems:

Catia Version 4

Catia Version 5

Unigraphics version 18

Unigraphics NX and NX2

Parasolid

STEP

IGES

 

The IGES interface reads files generated from any CAD system. Supported IGES entity types include:

 

 

Name

Type

Null Entity

0

Circular Arc Entity

100

Composite Curve Entity

102

Conic Arc Entity

104

Copious Data Entity

106

Plane Entity

108

Line Entity

110

Parametric Spline Curve Entity

112

Parametric Spline Surface Entity

114

Point Entity

116

Ruled Surface Entity

118

Surface of Revolution Entity

120

Tabulated Cylinder Entity

122

Transformation Matrix Entity

124

Rational B-Spline Curve Entity

126

Rational B-Spline Surface Entity

128

Offset Surface Entity

149

Boundary Entity

141

Curve on a Parametric Surface Entity

142

Bounded Surface Entity

143

Trimmed (Parametric) Surface Entity

144

Subfigure Definition Entity

308

Associativity Instance Entity

402

Property Entity

406

Singular Subfigure Instance Entity

408

 

For the German automotive industry, VDA file format is supported.  Supported VDA entity types include:

POINT

CIRCLE

CURVE

SURF

CONS

FACE

 

If CAD data is not available, eta/DSI has a complete geometry and surface building capability, which acts as an integrated CAD data generator. This is detailed in Chapter 6.

 

EXTENSIVE MODEL BUILDING FUNCTIONS

 

eta/DSI includes a comprehensive selection of functions for creating and modifying line data and CAD surfaces.  In addition to automeshing functions, element generation through 2-line, 4-line, 6-line and 8-line mesh creates beam, shell, and solid elements.

 

COMPREHENSIVE MODEL MODIFICATION FUNCTIONS

 

All aspects of the model may be modified using the pre-processing menus. All defined material, elements, nodes, contacts and analysis parameters may be modified, deleted, copied, etc., as required by the user.

 

FULL SYSTEM ASSEMBLY

 

The ASSEMBLY menu allows users to create assemblies which may be modified as a group. This includes part replacement and connectivity attributes of the model.

 

AUTOMESHING

 

eta/DSI's automeshing function easily eliminates 90% of the time required to mesh trimmed and standard surfaces. The automeshing function creates quadrilateral elements with a minimum of triangular elements.

 

Various automeshing algorithms are available, including Triangular Meshing, Paving Mesh and Topology Automeshing. A tetra element automesher is available, generating both 4-noded and 10-noded solid elements.

 

MATERIAL/ELEMENT PROPERTIES

 

eta/DSI supports all LS-DYNA and NASTRAN material and element property cards.  eta/DSI's ability to create and assign material and element properties directly on a displayed model greatly reduces the amount of editing required.  Definition cards appear at specific junctions in the session prompting the user for material/element properties.

 

A Material Library is available in the LS-DYNA environment, allowing users to select common ferrous and aluminum materials from a pre-populated set of material definitions.

 

Users also have the option to specify the analysis software (NASTRAN, LS-DYNA, RADIOSS, PAMCRASH) prior to assigning properties.

 

CONTACT INTERFACE

 

eta/DSI seamlessly interfaces with LS-DYNA, allowing the user to create and assign impact, sliding, or automatic interfaces for DSI applications.  eta/DSI displays contact properties in easily read and modified CONTACT CARDS with a high degree of speed and flexibility.

 

BOUNDARY CONDITIONS

 


eta/DSI's BOUNDARY CONDITIONS menu allows the user to quickly create and verify constraints and loads on DSI models.

 

MODEL INTEGRITY CHECKING FUNCTIONS

 

The functions in eta/DSI's MODEL CHECKER menu quickly validate models for element orientation, size, skew, connectivity, and interior angles.  Model validation default values are easily adjusted to suit the user's needs.

 

CONSTRAINTS

 

eta/DSI supports all LS-DYNA Constraint Cards for quick, easy definition and manipulation of joints, welds, rivets, etc.